Engineering for building construction has, in the past, produced a wide variety of structural designs. One of the more noteworthy of these designs is that described in Fuller, U.S. Pat. No. 2,682,235, which relates to a geodesic dome. The domes described in the Fuller Patent are said to provide protective shelter at a significantly lower weight per square foot of floor than had previously been possible using conventional wall and roof designs. The solution provided by Fuller is a dome-like structure prepared from substantially equilateral triangles.
Geodesic domes have, in the past, been used for a wide variety of structures. Spheres of approximately equilateral triangles in the geodesic pattern do, in fact, exhibit considerable strength. However, a number of practical problems are inherent in building structures based on a three-way grid defining substantially equilateral triangles. With either a spherical or hemispherical dome structure based on this pattern, each vertex intersection of surface planes represents the meeting of five or six triangular planes at a point. Such intersections require careful fitting and sealing. When a structure is patterned on a bisected sphere to form a dome, additional difficulties are encountered using equilateral triangles as the planar surfaces. These difficulties arise from the fact that alternate intersections of five or six triangles, in the geodesic pattern, define a surface which is either concave or convex with respect to the enclosed sphere. As a result, the perimeter of a geodesic dome, at the point of meeting a horizontal surface or other plane, defines a zigzag pattern. Moreover, the faces at the edge of the dome do not meet the planar surface at a right angle. These considerations make it difficult to incorporate basic architectural elements such as doors and windows into a geodesic dome.